Port cooler



Oct. 4, 1932. E J. MCDONNELL PORT COOLER 2 Shets-Sheet Filed June 25, 1931 INVENTOR E. J. M DONNELL Oct. 4, 1932.

PORT COOLER 2 Sheets-Sheet 2 Filed June 23, 1951 Tnw W Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE EDWARD J. MCDONNELL, 0F PITTSBURGH, PENNSYLVANIA,,ASSIGNOR TO BLAW-KNOX COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORIORATION OF PENNSYLVANIA PORT COOLER Application filed June 23,

This invention relates to port coolers for furnaces and is herein particularly described as applied toan open hearth furnace employing gaseous fuel.

In anopen hearth furnace the combustion air and, in the case of gaseous fuel, the gas as well, is preheated for combustion by passing it through a checker chamber which has been previously heated by the passage of products of combustion. The furnace is periodically reversed as is well understood. T he preheated gas and air are led to the furnace through uptakes and directed over the bath of metal in the furnace. It is important that the flame impinge upon the bath, which means that itmust be directed downwardly. It is therefore necessary to direct the incoming gas and air around an angle of more than 90 in carrying it from the uptake to the point of combustion. It is also important that the flame travel along the central portion of the furnace so as to save the brickwork and the banks as much as possible. This requires that the shape of the port through which the gas is supplied to the furnace be carefully determined in the first place, and that the shape be maintained throughout the furnace life.- It is also important that the velocit of the flame be sufficiently high so that a sharp flame is obtained. It is necessary to maintain the pressure in the furnace chamber at substantially atmospheric pressure, and to carefully conserve the relatively limited amount of energy available for directing the gaseous fuel through the port. There is a considerable loss of head in turning the gas around the corner at the top of the uptake and directing it to the port. I provide a structure wherein this loss is minimized.

The uptakes employed for supplying gas and air when the flame is travelling in one direction through the furnace are employed for taking off the products of combustion when the furnace is reversed, and, because of the carrying over of slag and other solid material, considerable erosion takes place. This erosion is highly undesirable for several reasons. It affects the shape of the port and the adjacent refractory structure and 1931. SCrialNO. 546,212.

thus adversely affects the operation of the furnace, and increases the cost of furnace maintenance.

It has been common practice for many years, as shown, for example, in Knox Patent 1,038,154, dated September 10, 1912, and Blair Patent 1,236,140, dated August 7, 1917, to provide metallic port coolers, which coolers serve to extend the life of the adjacent brickwork and minimize erosion thereof. practice is to use a cooler until it fails, and the failure invariably occurs when the furnace is hot, necessitating that the refining operation going on in the furnace be checked until the cooler can be replaced. With the coolers heretofore employed great difficulty has been encountered in their removal and there has been grave danger, due to the shape of such coolers, of their removal causing collapse of a large part of the adjacent brickwork. I provide for tapering the cooler and have found in practice that this greatly facilitates replacement. It is necessary to move the cooler toward the end of the furnace only a very sli ht amount in order to free it completely o the brickwork. It can therefore be pulled out without endangering the refractories, and a substitute cooler can be put in place and moved practically to its final position before it touches the brickwork, thereby further insuring against displacement of the refractories.

I prefer that the walls of the cooler shall be hollow for water circulation, and that they be made up of inner and outer plates, preferably uniformly spaced. This is of aid in effecting proper cooling throughout and gives an interior as well as an exterior tapered shape. An interior taper is important. It gives a larger cross sectional area at the top of the uptake and for a given volume of gas per minute the velocity at this point is lower. Therefore, the erosion of the brickwork is reduced and the initial shape of the gas passage is greatly prolonged. Furthermore, the loss of head as the gas is directed from the uptake to the portis materially lessened.

In the accompanying drawings illustrating a present preferred embodiment of the invention,

The

Figure 1 is a vertical longitudinal section through one end of an open hearth 't'uruacc having my improved cooler applied thereto.-

Figurez is a section taken on the line ll-ll of Figure 1: and

Figure 53 is a perspective view of the cooler.

The furnace shown in the drawings comprises a melting chamber :2 having afront wall 3 with door openings -ltherein and a back wall 5. The root' (3 is tapered down as shown at I to connect with the tapered roof 8 forming the top of the air port 9. The air port 9 is supplied with preheated air from uptakes 10. refractory arch l1. lying oetween the uptakes it). constitutes the top of the gas port 12. This port is connected by an inclined passage 13 to the gas uptake 14.

The port cooler is indicated generally by the reference character 15. It comprises hollow sides 16 connected by a hollow top portion 17 the cooler in cross section being in the form of an inverted U. It is made up of wrought metal plates bent to proper shape and welded together. The plates are shaped so as to form an inturned flange 18 Which defines the port proper. This flange is turned inwardly in an amount substantially equal to the thickness of a brick. so that a refractory brickwork lining it) may be built inside the cooler froma single thickness of bricks and form an inner face which is substantially a continuation of the inner face of the flange 18.

. As best shown in ignre 2 the sides l6 are inclined to one another so as to form a tapered shape. Because of this fact the cross sectional area of the port cooler adjacent the end of the furnace is considerably greater thanthe cross sectional area at the port proper. This gives a larger passage for the in comingand outgoing gases and materially reduces the erosion of the brickwork lining '19 and the end wall 20. The uptake 14 may be of a cross sectional area materially: larger than the port. The incoming gas therefore travels upwardly at relatively low speed, turns the corner at the top of the uptake without material loss of head, and then, as it travels through the tapered port structure, is increased in velocity and properly directed through the furnace.

Itwill be noted from Figure 2 that the center line b-bof the port cooler does not coincide with the center line aa of the furnace, but is directed toward the front wall 3.

This is done so as to offset any tendency of the flame to sweep to the back of the furnace by reason of infiltration of air through the door openings. This construction requires some corbelling of the brickwork adjacent the top of the uptake 14 as indicated at 21, but, nevertheless, by reason of the greater area of the port structure adjacent the end wall due to the tapered shape of the cooler, gives a larger In Figure- 3 I have shown the cooler in perspective. It will be seen that the. sides 16 taper toward the port end of the cooler and that the general shape of the cooler as a whole is that of part of a frustum ol'a cone. In Figure. 2- I have shown a U-shaped dotted line I) which constitutes the directrix of the exterior sln'i'zu'e,and have also shown a line G coustituting the generatrix of the exterior surface. The apex, because of lin'iitations of space, is not illustrated l'n1t it will be readily observed that the surface'swept out by the line (i when moving along the line I) and constantly passing through the apex will sweep out the desired outer surface. The inner surface is of similarconfiguration.

The cooling water is supplied through inlet pipes 22- terminating adjacent the inner end of the structure. The cooling water fills the hollow space between the inner and outer shells of the cooler and is taken off through a pipe 23.

In the event'that it :bBCOIIIES necessary to replace the cooler it is withdrawn axially. It will be noted from Figure 2 that there is a large amount of brickworkv in direct contact with theexterior shell of the cooler. In fact, such contact is necessary if adequate cooling of the brick arch 11 is to be had. Despite the fact that the furnace is operated at very high temperatures, the cooler may be withdrawn without endangering the brickwork because only a very slight amount of endwisemovement of the port cooler is required in order to clear the metal shell of the brickwork, after which the cooler may be quickly withdrawn and a new one substituted. I This constitutes an important adyantage of myinventi on. It is estimated that a delay on a modern open hearth furnace costs approximately one hundred dollars per hour, and, in addition to this, the workmen are subjected to extremely arduous conditions in effecting the repair. My improved port cooler makes it possible to effect axreplacement in a fraction of the time previously required, and, in addition, tl1ere is no danger of destroying the surrounding brickwork, which destruction would involve an extremely ditiicult repair job.

The bottom edges 24 of the sides 16 are inclined inwardly and upwardly, or to state it in anotherway, are tapered toward the top portion 7. This eliminates another cause of binding on withdrawal.

It has been shown that the shape of the cooler is approximately the shape of a part ofthe frustum of a cone. In the illustrated form the directrix of such cone is U-shaped making the two sides 16 parallel; but it may be circular, in which case the sides of the cooler will be curved the same as the top portion; or the direc'trix may be of other shapes. This is grue both for the exterior and interior surace.

55 passage than has been heretofore obtainable. While I have illustrated and described a present preferred embodiment of the invention, it will be understood that it is not thus limited but may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. A furnace port cooler comprising hollow sides connected by a hollow top portion, the hollow sides and top providing a continuous water space, and adapted to extend from a point above the uptake of the furnace to a port thereof, the sides tapering toward one another as the port end is approached.

2. A furnace port cooler comprising hollow sides connected by a hollow top portion so as to form a cooler which in cross section has the shape of an inverted U, the cooler being adapted to extend from a point above the uptake of a furnace to the port thereof, the sides tapering toward one another as the port end is approached.

3. A furnace port cooler comprising hollow sides connected by a hollow top portion and having a port end, the sides tapering toward one another as the port end is approached.

4. A furnace port cooler comprising sides connected by a top portion and means for cooling the sides and the top portion, the cooler having a port end, the sides tapering toward one another as the port end is approached.

5. A furnace port cooler comprising hollow sides connected by a hollow top portion, the sides and the top being inturned to form a port, the sides tapering outwardly from such ort. p 6. A furnace port cooler comprising hollow sides connected by a hollow top portion, the sides and the top being inturned to form a port, the sides tapering outwardly from such port, and a refractory lining for the. top and sides.

7. A furnace port cooler comprising hollow sides connected by a hollow top portion, the sides and the top being inturned to form a port, the sides tapering outwardly from such. port, and a refractory lining for the top and sides extending from the inturned portion.

8. A furnace port cooler comprising hollow sides connected by a hollow top portion, the sides and the top being inturned to form a port, the sides tapering outwardly from such port, and a refractory lining for thetop and sides, the refractory lining being of substantially uniform thickness.

9. A furnace port cooler comprising hollow sides connected by a hollow top portion and adapted to extend from a point above the uptake of a furnace to the port thereof, the cooler tapering in horizontal section from the uptake end to theport end. 3

10. A furnace port cooler comprising hollow sides connected by a hollow top portion and adapted to extend from a point above the uptake of a furnace to the port thereof, the cooler tapering interiorly and exteriorly toward the port end.

11. A furnace port cooler comprising hollow sides connected by a hollow top portion and adapted to extend from a point above the uptake of a furnace to the port thereof, the cooler tapering interiorly and exteriorly toward the port end. the sides and top of the furnace being of substantially uniform thickness.

12. A furnace port cooler comprising a hollow body having an interior surface with oppositely disposed side portions tapering tovgard one another and terminating in a port on 13. A furnace port cooler comprising a hollow body having an exterior surface with oppositely disposed side portions tapering tovgard one another and terminating in a port en 14. A furnace port cooler comprising a hollow body having an exterior surface with oppositely disposed side portions tapering toward one another and terminating in a port end, the bottom edges of the side portions being inclined inwardly and upwardly.

15. A furnace port cooler comprising a hollow body open at the bottom to overlie the uptake of a furnace and define the furnace port, the body tapering toward one end of the body constituting the port end of the cooler, the body being in the shape of a part of a frustum of a cone.

16.A furnace port-cooler comprising a hollow body open at the bottom to overlie the uptake of a furnace and define the -.-furnace port, thebody tapering toward one end of the body constituting the port end of the cooler, the exterior surface approximating the shape of a part of a frustum of a cone.

17. A furnace port cooler comprising a hollow body open at the bottom to overlie the uptake of a furnace and define the furnace port, the body tapering toward one end of the body constituting the port end of the cooler, the interior surface approximating the shape of a part of a frustum of a cone.

In testimony whereof I have hereunto set EDWARD J. MGDONNELL.

my hand. 

